Hi Aai, You are right. Thank you. --- Den tors 6/1/11 skrev Aai <[email protected]>:
> Fra: Aai <[email protected]> > Emne: Re: [Jprogramming] FFT > Til: "Programming forum" <[email protected]> > Dato: torsdag 6. januar 2011 12.58 > Hi Bo, > > Shouldn't it be: > > rou =: _1^2*i.%] > > ((_1^2%])-:[: r. 2p1 * i. % ]) 5 > 0 > > > Hallo Bo Jacoby, je schreef op 06-01-11 10:26: > > The page > > http://www.jsoftware.com/jwiki/JohnRandall/FourierTransformAndPolynomialMultiplication > > contains the definition > > rou=:[: r. 2p1 * i. % ] > > I'd like to supplement with the shorter definition > > rou=:_1^2%] > > but the page is write protected. Why? > > - Bo > > > > --- Den tors 6/1/11 skrev Roger Hui<[email protected]>: > > > >> Fra: Roger Hui<[email protected]> > >> Emne: [Jprogramming] FFT > >> Til: "Programming forum"<[email protected]> > >> Dato: torsdag 6. januar 2011 07.54 > >> http://www.jsoftware.com/jwiki/Essays/FFT > >> > >> cube =: ($~ q:@#) :. , > >> roots =: +...@]^:(0>[) (_1^2%]) ^ i...@-: > >> floop =: 4 : 'for_r. i.#$x do. (y=.{."1 y) ] > x=.(+/x) > >> ,&,:"r (-/x)*y end.' > >> fft =: (] floop&.cube > 1&ro...@#) > >> f. :. ifft > >> > >> This is a rare practical use of a high rank > array. > >> ("High" means greater than 4, say.) The only > other > >> "use" that I know of is the complete tensor of > order n. > >> http://www.jsoftware.com/help/dictionary/dccapdot.htm > >> > >> The expression ,&,:"r in floop can be > simplified to > >> ,:"r > >> if r is nonzero. This suggested that perhaps > the > >> definition > >> of atom0 ,: atom1 is incorrect. (Should have > shape 2 > >> > >> instead of 2 1.) > >> > >> > >> > >> > ---------------------------------------------------------------------- > >> For information about J forums see http://www.jsoftware.com/forums.htm > >> > > > > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > -- > Met vriendelijke groet, > =@@i > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
